Μελέτη δυναμικής συμπεριφοράς μεταλλικών κτιρίων υπο σεισμική διέγερση

The main goal of this thesis is the investigation of the modal spectrum analysis and specifically, the investigation and the comparison of the combination modal maxima SRSS and CQC for the calculation of the member forces of the structural members. However, apart from the classic statistical methods, where when we use them we lose the sign of the forces and the system is not in equilibrium, the seismic analysis was done through the IMR command (Individual Modal Response) of the static program STAAD.Pro, where it converts each mode into a load case and calculates the forces of members , holding their sign and the system is in equilibrium. Then, the results of the member forces of each significant mode that were calculated through IMR, are combined algebraically and compared with the results of the methods CQC, SRSS. Steel was chosen as the building material and Concentric Braced Frames (CBF) with “X” configuration were used as a lateral resistance system for the applied seismic forces. Parallel the properties and the principles of the braced frames were examined. In the context of seismic analysis, the static program STAAD.Pro is used, where during the modeling stage it was decided to examine three (3) main plane models and study the seismic phenomena and the behavior of low-rise buildings and high-rise buildings during an earthquake event. It is examined the behavior of the models in horizontal and vertical earthquake and in particular, the rate at which the seismic mass is incorporated in each mode shape during oscillation, the sign alternation of seismic member forces and whether the modal combination methods CQC, SRSS, IMRC are affected by that. Finally, it is examined the way that the physical characteristics (T, f, ωn) of the building models affect their seismic response. Another dimension of this research, in terms of the way that modeling affects the seismic behavior of structures, was the placement of intermediate nodes in the openings of the main beams of the models, where the three (3) main level ...